The overall goal of this project is to develop population databases for 7 highly polymorphic VNTR loci and 7 micro-repeat loci using automated PCR and image analysis procedures. The databases will provide the statistical basis for identity testing. The Phase I results of typing two VNTR loci using PCR and a high resolution polyacrylamide gel system indicate that discrete alleles of VNTR loci can be distinguished and scored properly. This Phase II proposal further addresses the selection of proper populations which will satisfy the needs of the identity testing market in the United States. Blood samples from a total of 1500 unrelated individuals from three ethnic groups will be collected. Overall, allele frequencies will be estimated from 900 chromosomes each for Caucasian Americans and for Hispanic Americans, and 1200 chromosomes each for Black Americans. The development of a PCR-based DNA identification system would be a significant improvement over the currently available systems for DNA typing. This system would require less DNA, reduce the time and expense of each typing analysis and allow analysis of degraded samples.These advantages would also expand the application of DNA typing into areas where it may not have previously been cost effective.